Naerok mill spindle runout

Hi all , recently purchased a Naerok mill drill for the garage,currently going through it and checking it all over.I decided to replace the spindle bearings as not knowing there history and they also were “notchy”,the spindle runout is hovering around .001”,is this acceptable helpful people?,can it be bettered or is this the norm for said machine.Also the dti is jumping around a bit indicating some vibration,I wondered if the sleeve bearings above the spindle need looking at?Anyway any help advice greatly appreciated.

I always recommend using the machine to cut metal before jumping to conclusions based on feel and a few measurements. The problem with accurate measurements is they're very easy to get wrong and then it's even easier to misinterpret what they mean. Approach with caution.

I find it better to cut known machinable metal with a sharp cutter at about the right rpm, depth of cut, and feed-rate. If the cut is the correct dimension and of reasonable finish, without horrible noises or smoke then the machine is 'good enough'. Note the need to test with suitable metal, not random scrap, and for the operator to drive the machine sensibly with a sharp cutter. The operator getting these wrong can produce worse results than a mildly worn bearing! So develop a reasonable level of experience before deciding what to do next.

Run-out of 0.001" suggests the bearings are on the way out but get to know the machine better before rushing to fix it.

Dave

How are you measuring your runout with what and where?

Bearings are brand new just fitted/repacked with quality grease.Tested runout of spindle on vee blocks when out of machine it was .00005”/nothing.using a .001” per graduation dial,I will admit I’ve been running the spindle whilst doing check which may contribute to needle dancing a bit,maybe I should check runout rotating spindle by hand?,and yes my next steps were to sut some metal!

Checking runout on end of spindle and also up in r8 taper

.001" isn't the best but you will be able to cut metal, I worked on large mills for many years and their spindle run out was far worse than yours.

Tony

Hmm I see,so what would an ideal runout be .0005” or less?

Well the less the better but we are talking about a hobby mill, an industrial machine costing £££'S should have little discernible internal spindle taper run out when new.

Tony

I can't imagine the reason for switching on the mill with a dial gauge on the spindle.

Vibration can come from the belts

Thanks all for your advice and input.With a bit of investigating it may appear I have not enough preload on the bearings,I’m going to remove the spindle again tighten them some more and recheck back in the machine,whilst tightening the draw bar I noticed I could still deflect the spindle by .001-.002” on the clock you could actually see the top of draw bar bolt move.New machine and learning curve!

Ok took spindle back out of machine and adjusted the preload,that and locking column,quill and “proper”! Tightening of draw bar cleaning spindle taper and making sure grub screw in r8 taper wasn’t deflecting collet chuck I achieved a respectable .0002” runout.I added this post as to help another beginner like myself who may search a similar thing. Thanks again all for your advice.

Well done! One small note: it is best not to run a dial indicator on a shaft revolving under power at anything above a couple of rpm. It puts too much strain on the dial indicator, and the dial indicator does not give an accurate reading at any kind of speed. It is a slow-reacting series of very high-ratio gears that don't do well under stress. Best to test your spindle by rotating it by hand, with no belt tension on the pulleys at all.

Yea I agree with that,off to find some decent beginners milling books now,first project is making tee nuts for the lovely old English vice I purchased.

Good stuff. Have fun. The contemporary treatise on the subject would be Milling for Beginners by our own Jason Bellamy.

Good result, you should be able to check preload by running the spindle at max rpm and it should only get luke warm after 15 minutes.

Hi I have the test report from the factory for my rdm350 with the specs that the mill should be when new the run out should be a max 0.02 at the top of the test bar and a max of 0.03 at a point 100mm below the first point.

Hope this helps

Interesting to know Kim,did you get a manual with yours?

I've got RDM 350, had for 30 odd years and have carried out many mods to it, some following George Turners articles in ME 1989. I made a power cross feed, using gears from photo copier and a car window up down motor, not all wiper motors are reverse able.5 or 6 years ago I fitted a pre owned 3 phase motor and inverter, what a difference that made. I'm sure there are better bench top mills around, but I very happy with mine. I've found the best source of information about machinery is the US Grizzly site, all though 'tony lathes' has some, and he say Naerok is the best of the bunch. I have a manual, but the picture on the front calls it a REXON, and models which were available are RDM 400-500/500MF,,nothing about a 350 I think that was for the US market, but no test report. John

Happy Christmas to all

Mine is badged “Naerok rdm400m”,I have found a lot of information on various forums and I downloaded a light manual for it from this forum.I also bought a “generic” manual from Tony on lathes uk site and it is very informative but really for the warco and rf 30 round column mills.There are similarities but would be nice to find a specific manual if there ever was one.Yes I’m excited to do lots of mods to mine to improve it,I fitted a 12v power feed to my myford lathe using a wiper motor and made the pulleys.One thing I’m gonna do first I think is make a power feed to move the head up and down,I can’t make my mind up though to either use a wiper motor again,or go down the stepper motor route,later I want to make power feed for x axis as well.I’m leaning towards stepper motor idea(although I have no experience with these!),coz maybe if I want to move column to final position,I think you can turn motor by hand with no signal.Maybe ha ha I dunno need more research.Yule tide blessings all.

Hi Yes it did come with a manual and test report however the manual was for the rdm 400m/500m/500mf

the manual has been edited in pen where there are differences I think the manual was the same for all as far as I can tell I think the main difference between the 350 and 400 was the table being slightly wider. I can't seem to upload an image of the test report which i have found useful in the past

Edited By Kim Garnett on 26/12/2022 11:08:40

Edited By Kim Garnett on 26/12/2022 11:10:28